Microarray systems are widely used for drug discovery, life science research, and clinical diagnostics. Future development of this technology is directed towards Point-of-Care (POC) applications including diagnosing disease, tracking epidemic disease outbreak, detecting biological and chemical weapons and hazardous conditions, and forensic analysis. However, these applications are limited due to the lack of instruments that provide hand-held portability, high sensitivity, low cost, and low battery power consumption. These problems stem from the current modality of fluorescent detection using costly and bulky optics.
The technology of sensing molecular species such as segments of, or entire strands of, nucleic acids such as DNA and RNA generally rely on optical methods in which an input optical signal interacts with chemical substances (known as probes) attached to known locations on a chip (such as a so-called gene chip). The optical response signal is received and analyzed, and depending on the response, an interaction of the probe with a target substance (e.g., a molecule having a complementary chemical sequence to a sequence on the probe) can be elucidated. The result can be used to determine whether an interaction of a known probe has or has not occurred with a specimen of interest, which can be used to determine whether the specimen of interest does or does not contain a specific target sequence or molecule.
In the prior art, it is necessary to have a source of the input optical signal which may include one or more specific wavelengths that interact with known probes, either alone or with optical sensitizing substances. In order to obtain the necessary wavelengths with sufficient purity, it is common to have to use optical processing techniques that rely on optical filters, optical diffraction, and/or multiple optical sources in order to provide suitable input optical signals at the specific wavelengths needed. In addition, it is necessary to have optical detectors that respond to the correct wavelengths that indicate the presence or absence of the target substances. In order to have a plurality of substance tests performed on a single chip, it is also often necessary to provide lenses (or arrays of lenses) that allow one to interrogate a plurality of known physical locations on the chip. All of the required optical technology that is needed adds significant cost and complication to the operation of optical systems and methods of testing for chemical substances in specimens of interest.
There is a need for systems and methods of analyzing specimens of interest for the presence or absence of chemical substances that avoid the complications and the costs associated with optical detection methods.